From patchwork Fri Sep 18 09:55:11 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Russell King X-Patchwork-Id: 7214811 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 15D359F380 for ; Fri, 18 Sep 2015 09:57:54 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2844620946 for ; Fri, 18 Sep 2015 09:57:53 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3FB8520900 for ; Fri, 18 Sep 2015 09:57:52 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZcsP2-0005T1-W7; Fri, 18 Sep 2015 09:56:25 +0000 Received: from pandora.arm.linux.org.uk ([2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZcsOy-00054T-09 for linux-arm-kernel@lists.infradead.org; Fri, 18 Sep 2015 09:56:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=arm.linux.org.uk; s=pandora-2014; h=Date:Sender:Message-Id:Content-Type:Content-Transfer-Encoding:MIME-Version:Subject:Cc:To:From:References:In-Reply-To; bh=Pm50Op+gYXJHdl+WQ+j/rpOn4jwLe2t/fqYpfdlMJAk=; b=bmJAc4CzHHieOD1N5LRO2o96VoMNjibTWv5XOLdWjY+z3kJe6akaG0wT4jex/WWZc3+PDy8UHrCUzjLoi2YvMENONHvMjMZQ6eni1G0Hq26+NOfffcMMKsgVKD5GhMt4jlqNQ8s89Yjc0EzmNbRtI+upv+dMfUBZrXmkd5yvl64=; Received: from e0022681537dd.dyn.arm.linux.org.uk ([2001:4d48:ad52:3201:222:68ff:fe15:37dd]:53242 helo=rmk-PC.arm.linux.org.uk) by pandora.arm.linux.org.uk with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZcsNz-0004tj-5N; Fri, 18 Sep 2015 10:55:19 +0100 Received: from rmk by rmk-PC.arm.linux.org.uk with local (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZcsNr-0001Fq-W1; Fri, 18 Sep 2015 10:55:12 +0100 In-Reply-To: <20150918094625.GB21084@n2100.arm.linux.org.uk> References: <20150918094625.GB21084@n2100.arm.linux.org.uk> From: Russell King To: Florian Fainelli Subject: [PATCH 4/7] of_mdio: fix MDIO phy device refcounting MIME-Version: 1.0 Content-Disposition: inline Message-Id: Date: Fri, 18 Sep 2015 10:55:11 +0100 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150918_025621_101390_78B31A77 X-CRM114-Status: GOOD ( 15.12 ) X-Spam-Score: -2.7 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Petazzoni , devicetree@vger.kernel.org, Sunil Goutham , Robert Richter , Frank Rowand , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Rob Herring , Michal Simek , netdev@vger.kernel.org, Soren Brinkmann , Iyappan Subramanian , Grant Likely , Li Yang , Keyur Chudgar , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP bus_find_device() is defined as: * This is similar to the bus_for_each_dev() function above, but it * returns a reference to a device that is 'found' for later use, as * determined by the @match callback. and it does indeed return a reference-counted pointer to the device: while ((dev = next_device(&i))) if (match(dev, data) && get_device(dev)) ^^^^^^^^^^^^^^^ break; klist_iter_exit(&i); return dev; What that means is that when we're done with the struct device, we must drop that reference. Neither of_phy_connect() nor of_phy_attach() did this when phy_connect_direct() or phy_attach_direct() failed. With our previous patch, phy_connect_direct() and phy_attach_direct() take a new refcount on the phy device when successful, so we can drop our local reference immediatley after these functions, whether or not they succeeded. Signed-off-by: Russell King --- drivers/of/of_mdio.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c index 1350fa25cdb0..a87a868fed64 100644 --- a/drivers/of/of_mdio.c +++ b/drivers/of/of_mdio.c @@ -197,7 +197,8 @@ static int of_phy_match(struct device *dev, void *phy_np) * of_phy_find_device - Give a PHY node, find the phy_device * @phy_np: Pointer to the phy's device tree node * - * Returns a pointer to the phy_device. + * If successful, returns a pointer to the phy_device with the embedded + * struct device refcount incremented by one, or NULL on failure. */ struct phy_device *of_phy_find_device(struct device_node *phy_np) { @@ -217,7 +218,9 @@ EXPORT_SYMBOL(of_phy_find_device); * @hndlr: Link state callback for the network device * @iface: PHY data interface type * - * Returns a pointer to the phy_device if successful. NULL otherwise + * If successful, returns a pointer to the phy_device with the embedded + * struct device refcount incremented by one, or NULL on failure. The + * refcount must be dropped by calling phy_disconnect() or phy_detach(). */ struct phy_device *of_phy_connect(struct net_device *dev, struct device_node *phy_np, @@ -225,13 +228,19 @@ struct phy_device *of_phy_connect(struct net_device *dev, phy_interface_t iface) { struct phy_device *phy = of_phy_find_device(phy_np); + int ret; if (!phy) return NULL; phy->dev_flags = flags; - return phy_connect_direct(dev, phy, hndlr, iface) ? NULL : phy; + ret = phy_connect_direct(dev, phy, hndlr, iface); + + /* refcount is held by phy_connect_direct() on success */ + put_device(&phy->dev); + + return ret ? NULL : phy; } EXPORT_SYMBOL(of_phy_connect); @@ -241,17 +250,27 @@ EXPORT_SYMBOL(of_phy_connect); * @phy_np: Node pointer for the PHY * @flags: flags to pass to the PHY * @iface: PHY data interface type + * + * If successful, returns a pointer to the phy_device with the embedded + * struct device refcount incremented by one, or NULL on failure. The + * refcount must be dropped by calling phy_disconnect() or phy_detach(). */ struct phy_device *of_phy_attach(struct net_device *dev, struct device_node *phy_np, u32 flags, phy_interface_t iface) { struct phy_device *phy = of_phy_find_device(phy_np); + int ret; if (!phy) return NULL; - return phy_attach_direct(dev, phy, flags, iface) ? NULL : phy; + ret = phy_attach_direct(dev, phy, flags, iface); + + /* refcount is held by phy_attach_direct() on success */ + put_device(&phy->dev); + + return ret ? NULL : phy; } EXPORT_SYMBOL(of_phy_attach);